The invention is described in further detail below with reference to the Figures, wherein like elements are referenced by like numerals throughout.
Electrical contacts, otherwise referred to as terminals or contact pins, are used in the electronics industry in conjunction with printed circuit boards (PCB's), electrical panels, connector cables and other devices, for making electrical connections. As used herein, the terms "electrical" and "electronic", and conjugations thereof, are synonymous and interchangeable, and refer to any component, circuit, device or system which utilizes the principles of electricity in its operation.
A plurality of the contact pins are frequently mounted in an insulative male connector housing, with one end of the contacts extending from the connector housing so as to make mechanical and electrical contact with a female mating connector. In a typical high pin count (HPC) header, for example, which is a commercially available male connector, contacts or wire pins which normally have a circular or square cross section are staked into round holes in a housing. Retention of the pins in the housing is achieved by a press fit, otherwise known as "negative clearance", between the contact pins and the holes of the connector housing. The contact pins are typically made from bronze, brass, steel, stainless steel or copper alloy and the connector housing is typically made from a plastic or resin type material. During the staking process, the holes of the connector housing can become enlarged and deformed due to the negative clearance between the pin and the perimeter of the holes. This degrades the ability of the connector housing to securely hold the contact pins in their proper position and alignment. As used herein, the terms "connector", "header", "housing", and any combination and/or conjugation thereof, are synonymous and interchangeable, and refer to any body, panel, board, device or structure having secured contact pins therein for providing electrical and/or mechanical connections.
It is well known to provide recesses and fins, otherwise known as "stars", on the longitudinal side surface of contact pins to form a retention portion on the contact pins. These star retention portions provide extra holding power when the contact pin is inserted into a connector housing. The recesses and their corresponding fins are formed by stamping technology in which the fins are forced or extruded outwardly as the recesses or grooves are stamped into the retention portion of the contact pin.
Typically, contact pins are formed from square or round wire, or strip metal, made from either steel, stainless steel, bronze, brass or copper alloy. The star feature is a section of the pin that has been expanded by striking the square section, or diameter, of the wire or strip with chisel-like tools on four sides at the same time. This action causes four "V" shaped depressions to be produced in the wire. Between the depressions, a fin is raised above the original diameter or in the case of a square wire, above the diagonal dimension of the wire. Therefore, the star feature is an enlarged portion of the contact pin and is used to provide increased press fit between the contact pin and a hole of a connector housing.
Even with the utilization of these star retention features, however, the connector industry is plagued by defective connectors due to inadequate retention of the contact pins in their connector housings. Many problems occur in connectors due to loose contact pins. These pins may fall out or move partially out of their intended position causing mechanical and/or electrical failure. Past solutions that have been proposed to solve this problem have included increasing the amount of press fit, or negative clearance, between the holes of a connector housing and the contact pins. This is accomplished by making the star feature larger or the hole smaller. However, this approach has not been effective because it has caused cracking or warpage of the connector housing. Similarly, contact headers on PC boards, or the PC boards themselves, have been known to break or crack if a pin, or the star feature of a pin, is too large.